If you stride through the gym straight to the dumbbell rack, grab the first set of weights you see and immediately get to curling, your biceps-building workout is probably too rushed. To really emphasize the exercise's full range of motion and muscle contraction, through which you'll reap the most muscle-building benefit, you need to focus on form. One of the best ways to do that is to concentrate. By that, we mean that you need to try concentration curls.

The concentration curl is the antithesis of sloppy, rushed reps performed directly in front of the weight rack mirror. Instead of racing to the end of each set and piling up junk volume, your aim is to isolate the biceps, putting yourself in a position that eliminates and cheating or body English from taking the focus off the muscle.

There's more to the concentration curl than just jamming your elbow into your thigh and dialing down your reps. The move is a bodybuilding classic, but going through the motions won't get you the gains you're hoping to achieve. "When I see people do it in the gym, a lot of times these days they're not really executing it well," says Men's Health fitness director Ebenezer Samuel, C.S.C.S. The major focus should be on getting that muscle contraction, but your posture on the bench should be totally on point in order to reap the benefits.

Watch Samuel guide MH fitness editor Brett Williams, NASM-CPT through the cues you need to perfect the concentration curl.

Benefits of the Concentration Curl

The concentration curl allows you to really isolate your biceps muscle—the ultimate aim of all curl variations—more effectively than other versions of the exercise. Your position forces you to move only at the elbow joint, allowing you to emphasize the muscle contraction without your shoulders or momentum aiding in the lift.

The exercise also helps to target the peaks of the biceps, since you're able to really home in on that contraction. The position is an excellent tool to help harried lifters to slow down and really emphasize form and the mechanics of a curl.

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How to Do the Concentration Curl

Follow these form cues to learn how to do the concentration curl. Once you've read the step-by-step directions, follow along for some higher-level tips from Samuel to dive deeper into the exercise.

●Sit on a bench, with a dumbbell between your legs.

●Grab the dumbbell with one hand, then place your upper arm (your triceps muscle) against your thigh. Your goal should be to keep your arm perpendicular to the ground throughout the whole movement.

●Tighten your core and engage your shoulder blades to create tension and reinforce posture.

●Make a fist with your off hand and extend your non-working arm out to the side. This allows you to use your core to balance and remove any leverage that would take away from biceps engagement.

●Curl the weight up with control, keeping the wrist in a neutral position. Emphasize the squeeze at the top of the rep; avoid any backwards lean or shoulder movement, keeping the focus on the biceps.

●Perform 3 sets of 8 to 12 reps per arm, or 3 minutes alternating 30 seconds of work per arm.

Arm to Thigh

Eb says: The most common mistake you see with the concentration curl comes in the initial setup: Many people try to wedge their elbow into their thigh. But doing basically lets you use both knee and elbow as one big fulcrum, essentially making the curl easier and taking tension off the biceps.

Avoid this by wedging your upper arm into your thigh, thinking of driving the meatiest part of your triceps in there. You'll have to hinge your waist forward a bit more to do this, but you'll get more out of the entire curl.

Upper Arm Perpendicular

Eb says: Once you're in this position, you're responsibility is to maintain this position. Your upper arm should, for the life of each set, be perpendicular to the ground and stay perpendicular.

You'll be tempted to lean back as you curl, just as you are on nearly every curl. But fight to keep your upper arm perpendicular to the ground the entire time. Watch yourself in a mirror if possible to check technique.

Don't Overcurl

Eb says: One of the biggest problems guys have with the concentration curl (and any curl, really) is a tendency to chase an arbitrary endpoint. You may think you have to get the dumbbell to touch your shoulder, for example. Don't do that.

Curl up only as high as you can before you start to feel your triceps losing contact with your thigh. As long as your forearm is higher than parallel to the ground, you'll be engaging your biceps. If you try to go beyond this point and your elbow starts shifting forward, all you're doing is taking stress and focus off the biceps.

Want to master even more moves? Check out our entire Form Check series.

Headshot of Brett Williams, NASM
Brett Williams, NASM

Brett Williams, a fitness editor at Men's Health, is a NASM-CPT certified trainer and former pro football player and tech reporter who splits his workout time between strength and conditioning training, martial arts, and running. You can find his work elsewhere at Mashable, Thrillist, and other outlets.

Headshot of Ebenezer Samuel,  C.S.C.S.

Ebenezer Samuel, C.S.C.S., is the fitness director of Men's Health and a certified trainer with more than 10 years of training experience. He's logged training time with NFL athletes and track athletes and his current training regimen includes weight training, HIIT conditioning, and yoga. Before joining Men's Health in 2017, he served as a sports columnist and tech columnist for the New York Daily News.